Tube bender and cutter

ABSTRACT

A cutting and bending machine for square or rectangular tubing in which a cutting hydraulic shear is pivotally mounted so as to swing down from the cutting position and help form a working surface upon which the bending operation can be completed. The bending portion comprises an adjustable mandrel adapted to engage a variety of sizes of tube and slidably force the tube between two parallel bending posts.

United States @Wfifi 91 Kroetcli [54] TUBE BENDER AND CUTTER [76] Inventor: Arthur A. Kroetch, PO. Box 256,

Philips, S. Dak. 57567 22 Filed: Aug. 20, 1970 21 Appl. No.: 65,434

52 u.s.c1. ..72/332,72/3s9,72/404, 83/513 51 1113.01. ..B21d9/10 [58] Field of Search ..72/389, 386, 385, 380, 404, 72/324, 326, 332, 337, 212, 213, 369;

[56] References Cited UNITED STATES PATENTS 2,998,838 9/1961 Byrd ..72/389 1,803,542 5/1931 Boyle ....72/332 2,382,266 8/1945 Simonsen ..72/389 1 Apr. 3, 1973 2,451,302 10/1948 Peters ..72 3s9 2,779,382 1 1957 Anello ..72 3s9 3,150,551 9/1964 Spengler ..83/694 Primary ExaminerRichard J. l-lerbst Assistant ExaminerGene P. Crosby Attorney-Robert M. Dunning [57] ABSTRACT A cutting and bending machine for square or rectangular tubing in which a cutting hydraulic shear is pivotally mounted so as to swing down from the cutting position and help form a working surface upon which the bending operation can be completed. The bending portion comprises an adjustable mandrel adapted to engage a variety of sizes of tube and slidably force the tube between two parallel bending posts.

17 Claims, 16 Drawing Figures PATENTEDAPR 3 I975 SHEET 1. 0F 5 a M Rm K Arr w! M m ATTORNEY PATENTEDAPRB I975 3.724.256

SHEET 2 or 5 INVENTOR ARTHUR A. KPOETCH BY @UAMM ATTORNEY PATENTEDAPRS 1973 3,724,256

SHEET 3 OF 5 123 J o 0 i INVENTOR Z4 ARTHUR A.KF?O'TCH BY @mgw PATENTEU APR 3 I975 SHEET L 0F 5 INVENTOR Apr/1UP 4. KPOETCH BY 90%.Qmqw

ATTORNEY TUBE BENDER AND CUTTER BACKGROUND OF THE INVENTION A need exists in the prior art for a compact machine capable of bending and cutting square tubing which tubing is difficult to handle due to its structural shape. Square or rectangular tubing does not form easily into a radius bend and usually buckles or creases unexpectedly causing a weak or misshaped bend. Thus, it is desirable to have a machine which can manipulate square or rectangular tubing in such a way as to form a smooth radius bend in the tubing. The present invention provides such a device.

There is also a need in the prior art for a machine which cannot only bend tubing but cut the tubing to the proper lengths. The cutting station should be handy to the bending unit but not interfere with the operation of the bending unit. Further desirable features include an ability to perform all of the above functions with a minimum of hydraulic circuitry. The machine should permit operation from any side to be maximally convenient and further the machine should be adjustable to easily handle a variety of different sizes of square and rectangular tubing. The present invention achieves all of the above objectives and more as is described below.

SUMMARY OF THE INVENTION Briefly, the present invention combines a tube bending unit which operates horizontally with a tube cutting unit which operates vertically. The vertical cutting unit is pivotally mounted to the horizontal bending unit so that it may be rotated down into a flat position so as not to interfere with the tube bending unit and further to provide additional working surface for the tube bending unit. The tube cutting unit incorporates a hydraulically actuated cutting shear positioned by adjustable spacers so that it can be used to cut a variety of sizes and shapes of rectangular tube.

Thebending unit operates to bend the tube between two parallel rotatable posts by means of a sliding cylindrical mandrel which is adjustable to accept a variety of sizes of tubing. The mandrel utilizes a special central ridge or kinker which produces a fold in the tube as it is being bent thus displacing excess material in the tube wall so as to permit an even strong bend in the tube without any unexpected creases or weak points. A single hydraulic supply pump operates both machines through simplified controls which are accessible from either side of the machine so as to make operation of the device most convenient. It may therefore be seen that it is an object of my invention to provide an improved tubing bender and cutter. It is a further object of my invention to provide a combined bending and cutting machine which is relatively compact so that the bulky tubing need be moved only a small distance in order to be cut to the desired length.

Further objects and advantages will become. apparent to those skilled in the art upon consideration of the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the combination bending and cutting machine of the present invention showing the cutting unit in the vertical operating position.

FIG. 2 is a top view of the machine of FIG. 1 with the cutting unit still in a vertical operating position.

FIG. 3 is a side view of the machine of FIG. 1 as seen from the rear with the cutting unit pivoted down into the stored position where it does not interfere with the operation of the bending unit.

FIG. 4 is a partially sectional side view of the upper portion of the machine showing specifically the bending mandrel and the operating mechanism therefor.

FIG. 5 is a sectional end view of the upper portion of the machine showing the mandrel in detail and the guideways which support the mandrel for sliding movement.

FIG. 6 and FIG. 7 show in succession how the tubing is bent between two posts by the sliding motion of the adjustable mandrel.

FIG. 8 is another sectional view of the top of the adjustable mandrel showing the raised rim or kinker which operates to fold in the excess material in the wall of the tubing during the bending operation.

FIG. 8A is a plan view of FIG. 8.

FIG. 9 is a perspective view of a piece of tubing that has been bent and FIG. 10 is a section ofthe same tubing taken along line 1010 in FIG. 9.

FIG. 11 is a sectional view of one of the rotatable bending posts against which the tubing is bent.

FIG. 12 is a side view of the housing of the cutter unit with the access door open so as to show the actuating mechanism for the shear.

FIG. 13 is a sectional view of the cutter unit taken on line 13-13 in FIG. 12.

FIG. 14 is another sectional view of the cutter unit of FIG. 12 taken along line 14- 14 in FIG. 12.

FIG. 15 is a schematic diagram showing the hydraulic circuitry utilized to operate the various mechanisms in the machine of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 the bending and cutting machine is shown in perspective. A base housing portion 10 contains most of the hydraulic equipment and further supports a smaller upper bending unit housing 12, which encloses the horizontally operating bending unit. Fastened to the side of upper housing portion 12 is the cutter housing 14 which is pivotally mounted at one bottom corner about a-pivot bolt '15 which may be more easily seen by a brief reference to FIG. 2. A spring loaded support pin 17 at the other bottom corner of cutting housing 14 looks cutting housing 14 in place by sliding into a hole in the side of upper housing portion 12. A spring 11 urges pin 17 into the hole. Grasping handle 19 on the end of pin 17 and withdrawing the pin from the hole in housing 12 permits one to pivot cutter housing 14 down onto the top surface of base housing 10 so as to be out of the way of the operations of the bending unit in upper housing portion 12. It may be seen that when cutting housing '14 is lowered into position the side of housing 14 may actually afford additional working space for the bending unit. 7

The controls on the machine include a handle 16' which is used to activate either the cutter or the bending unitv by moving an internal selection valve in the hydraulic circuitry which will be described in detail with respect to FIG. 15. Operation of either the bending or the cutting unit may be controlled by any of four pedals 18, 20, 24 or 26 positioned at the four comers of the machine. Pedals 18 and 20 are connected to a common rod 22 while pedals 24 and 26 are connected to a common rod 28. In FIG. 3 it may be seen that rod 28 and rod 22 are connected respectively to levers 48 and 50 which are in turn connected by means of a pair of rods 51 and 52 to a common lever 53 which operates a valve 54 which also will be described with respect to FIG. 15. Returning to FIG. 1 it may be noted that an additional hand rod 20 may be attached to one of the pedals so that they may be operated by hand.

The bending operation will be described with respect to FIGS. 1,2, 3, 4, 5, 6, 7, and 8. In FIG. 1 it may be seen that a piece of tubing 32 is inserted into the corners of a pair of right angle stops 33 and 34 positioned on top of housing 12. To bend the tube, selector switch 16 is positioned so as to activate the bending unit as will be described later. Any one of the four pedals or the hand bar 20' is rotated so as to move the connection linkage visible in FIG. 3 and energize hydraulic pump 56. Pump 56 is driven by a motor 58 through a suitable drive belt 60. The hydraulic fluid from pump 56 is directed to a hydraulic cylinder 62 which cylinder is best seen by reference toFIG. 4.

Cylinder 62 is internally mounted in housing 12 between a fixed pin 63 and sliding mandrel assembly 30 so that the resultant extension of a push rod 64 from cylinder 62 moves mandrel assembly 30 to the left in FIG. 4 until it reaches an adjustable threaded stop 66. The position of threaded stop 66 is adjustable by a hand knob 40 which is best seen in FIG. 1. In FIG. 1 it may be seen that the sliding mandrel assembly 30 follows a groove 42 carrying the tubing between a pair of bending posts 36 and 38. The construction of posts 36 and 38 is such that the outside surface is free to rotate with the slight sliding motion of the sides or ends of tube 32. Posts 36 and 38 are shown in section in FIG. 11.

In FIG. 1 and FIGS. 6, 7 and 8 it may be seen that mandrel 30 has a slot 69 in it of just the right size to accept tube 32. FIG. 6 demonstrates how as mandrel 30 slides to the left, bar 32 engages bending posts 36 and .38. As mandrel 30 continues to slide to its full leftward position, bar 32 is caused to' be bent around mandrel 30 as shown in FIG. 7. To assist in this bending operation a small rim or kinker 79 is utilized on the mandrel inside the accepting slot 69 as shown in FIG. 8 which folds in the side of member 32 to assist in making a smooth even radius bend. Kinker 79 insures that the excess material is uniformly distributed, thus, preventing distortions in the walls of the square tubing. When the tube is bent it takes the form shown in perspective in FIG. 9 and in section in FIG. 10.

Once the bend is completed, the operator of the 'machine moves one of the pedals or the control handle 30 in the opposite direction so as to change the position of valve 54 on pump 56. Cylinder 62 returns to its contracted position and slidable mandrel 30 slides back to the beginning position. Referring to FIG. 1 and to FIG. 7 it may be seen that on the return stroke the now bent arms of tube 32 engage the upright portions of stops 33 and 34 on the top of housing 12 which action operates to extract tube 32 from slot 69 in mandrel 30. The tube 32 may then be removed from the machine and manually inserted into the cutter whose operation will be described presently. 1

Adjustable mandrel 30 is shown in greater detail with respect to FIG. 2 and FIG. 5. Referring simultaneously to these two figures it may be seen that adjustable man- 'drel 30 comprises a central bolt 70 which rides in groove 42 by means of a flange 71. The lower portion of bolt 70 passes through and is connected to a generally rectangular member 72 which rides along a pair of guide members 73 and 74 by means of four roller wheels 44, 45, 46, and 47. Roller wheels 44 through 47 are mounted in member 72 by means of vertically disposed pins around which they can rotate and roll along the indented ledges in guide members 73 and 74. A pair of bearing plates 75 and 76 are positioned at the top of member 72 to provide a smooth bearing surface for sliding against the underside of the horizontal face of housing 12. Member 72 also has a tongue 77 at its rear which permits connection to actuating arm 64 and hydraulic cylinder 62. (See FIG. 4)

Referring specifically to FIG. 5 the top of adjustable mandrel 30 will now be described. Surrounding bolt 70 is a bending mandrel 78 which has the kinker or ridge 79 formed thereon the function of which has already been described. A pair of thin spacer rings 80 and 81 are positioned between bending mandrel 78 and a pair of annular members 82 and 83. Members 82 and 83 operate to form slot 69 therebetween and have small notches in their corners designed to accept spacer rings 80 and 81. It should be noted in FIG. 5 that if either annular ring 82 or 83 or both are reversed in position they will rest in a position which forms a wider slot 69 by virtue of the lack of a notch to accept spacer rings 80 and 81. In addition, different size widths of spacer rings 80 and 81 may be chosen so as to provide a large number of variations in the width of slot 69 so that adjustable mandrel 30 may accommodate a variety of sizes of tubing. Finally a retainer plate 84 is mounted to the end of bolt 70 by means of a retainer bolt 85 so as to hold the entire assembly together. I

Returning to FIG. 1 the operation of the cutter may be explained. In order to cut tubingthe cutter housing 14 is brought to the vertical position shown in FIG. 1. Pin 17 locks cutter housing 14 in place by sliding into a hole in the side of housing portion 12. Referring to FIG. 12 a detailed enlarged side view of cutter housing 14 is shown. An access door 13 is shown open and cutaway for a better internal view of housing 14. Another hydraulic cylinder is positioned within housing 14 and fastened to the top by means of a secured pin 92. An extendable push rod 91 from hydraulic cylinder 90 is connected to a sliding guide member 94 which in turn is connected to a pointed shear blade 96. Guide member 94 travels between a pair of replaceable spacer blocks 97 and 98 which spacer blocks have narrow slots in them designed to accept blade 96. Spacer blocks 97 and 98 are held in position within housing 14 I tioned below the first pair of cross members. Positioned p at the bottom of housing 14 are two V-shaped stock rests 108 and 109 upon which the square tubing (shown as tube 32) can be rested. Selector handle 16 is moved to the cutter position so that the hydraulic controls will actuate the cutter. One of the foot pedals or the hand pedal is used to direct hydraulic fluid from pump 56 through switch 54 to hydraulic cylinder 90. Push rod 91 extends forcing guide member 94 and shear blade 96 down through tube 32 positioned on V blocks 108 and 109. Blade 96 passes between V blocks 108 and 109.

In FIG. 12 tube 32 is shown as a square piece resting on V blocks 108 and 109. If rectangular tubing is to be cut the point of shear blade 96 should be displaced so as to contact the point formed by the sides of the rectangular piece of tube. In this situation spacer blocks 97 and 98 are replaced with slightly offset spacer blocks so as to insure that the point of shear blade 96 strikes directly on the corner of the rectangular piece of tubing.

Two sectional views through FIG. 12 are presented in FIGS. 13 and 14. Reference to FIG. 13 will show in detail how shear blade 96 is fitted into slots in spacer blocks 97 and 98 which are in turn solidly mounted between cross members 100 through 103 and further located by means of additional spacer blocks 121 and 123. Looking at a somewhat lower cross-sectional view in FIG. 14 it should be noted that the V-shaped resting surface upon which the tube is positioned is increased in area by means of two additional V-shaped blocks 115 and 116 and a pair of V-shaped plates 1 18 and 120 mounted along side V blocks 108 and 109.

Turning to FIG. it may be seen how the hydraulic system operates to actuate the various cylinders as described heretofore. Pump 56, driven by motor 58, pumps hydraulic fluid from a reservoir 150 through a selector valve 152. Valve 152 is controlled by lever 16 as explained with respect to FIG. 1 and diverts hydraulic fluid to either the cutting or the bending unit through hydraulic hose 154 or hydraulic hose 156 respectively. Hydraulic valve 54, constructed according to principles well known to those skilled in the art, is operated by any of the pedals, as described earlier (shown as pedal in FIG. 15) through the linkageof levers and rods shown schematically by a dashed line 158 in FIG. 15. In the position shown valve 54 directs hydraulic fluid through line 161 to cylinder 90 so as to hold blade 96 in an up or rest position. The return route for the hydraulic fluid is through hose 160 and return line 162 to reservoir 150. To activate the cutting blade, handle 16 is used to move selector valve 152 and direct fluid through line 154. Then valve 54 is moved to the left so as to reverse the connections and direct hydraulic fluid through line 160 to cylinder 90 so as to drive shear blade 96 through the metal tube. The blade is retracted by returning valve 54 to the position shown in FIG. 15.

Bending mandrel 30 is operated in the same fashion through valve 152, valve 54, and hydraulic cylinder 62. The hydraulic fluid is pumped through line 166 when valve 54 is moved to the right so as to slide adjustable mandrel 30 to form the bend. To retract mandrel 30, valve 54 is returned to the position shown in FIG. 15 so that hydraulic fluid enters cylinder 62 through hose 165. Since the stock is bent until mandrel 30 comes against adjustable stop 66 as shown in FIG. 4, a relief bypass valve 170 is incorporated into hose l66'which permits hydraulic fluid to pass directly back to the reservoir through a hose 167 in the event the pressure becomes too high. Bypass valve 170, thus, operates to prevent damage to stop 66 and alleviate any overloading of the hydraulic system. Of course, the hydraulic system shown in FIG. 15 is only exemplary and a number of motive systems could be substituted to provide the movements and controls indicated as necessary to this machine. In fact, a number of modifications could be made to the present invention without departing from the spirit and scope of the claimed invention such as modified guideways, modified control linkage, and different designs in the shapes of the spacing rings and arrangements for changing the configuration of the bending mandrel 30.

I claim:

1. A machine comprising in combination:

a housing,

slidable means on said housing adapted to engage a piece of tube and bend it against stationary post means,

means for sliding said slidable means, and

tube cutting means mounted on said housing adapted to pivot on said housing into a position which does not interfere with the bending of said tube against said post means.

2. The machine of claim 1 in which said tube cutting means comprises a hydraulic cylinder connected to a pointed shear blade operable to force said blade through a piece of tube carried by-a notched support member, said cylinder and said notched support member carried by a cutter housing.

3. The structure of claim 1 and including annular members above and below said bending mandrel to define a slot adapted to accommodate the tube to be bent.

, 4. The machine of claim 1 in which said slidable means comprises an adjustable grooved mandrel, which groove is shaped to accept said tube and to approximate the desired bend. 1

5. The machine of claim 4 in which said groove includes a kinker ridge to fold in the side of the tube during the bending operation.

6. The apparatus of claim 5 including stop means on said housing adjacent said adjustable mandrel operable to force the bent tube out of said groove when the adjustable mandrel slides away from'said post means. I

7. The apparatus of claim 6 in which said means for sliding comprises a hydraulic cylinder connected to said mandrel so as to slide said mandrel along guideway means in said housing.

8. The apparatus of claim 7 in which said post means comprise rotatable posts on said housing on each side of said guideway means. v

9. The machine of claim 5 in which said tube cutting means comprises a hydraulic cylinder connected to a pointed shear blade operable to force said blade through a piece of tube carried by a notched support member, said cylinder and said notched support member carried by a cutter housing.

10. The machine of claim 8 in which said tube cutting means comprises a hydraulic cylinder connected to a pointed shear blade operable to force said blade through a piece of tube carried by a notched support member, said cylinder and said notched support member carried by a cutter housing.

11. A machine comprising in combination: a housing, slidable means extending out of said housing adapted to slide along a guide means, engage a piece of tube, and bend it against stationary postmeans positioned on each side of said guide means, means for sliding said slidable means operable to be activated manually, said slidable means includes a grooved mandrel, which groove is shaped to accept said tube and to approximate the desired bend, said groove includes a kinker ridge to fold in excess material in the walls of the tube during the bending operation.

12. The apparatus of claim 11 including stop means on said housing adjacent said guide means positioned to force the bent tube out of said groove as the mandrel slides away from said post means.

13. The apparatus of claim 12 in which said means for sliding comprises a hydraulic cylinder connected to said mandrel and said post means comprise rotatable posts on said housing on each side of said guide means.

l4.'A tube bending machine including:

a housing having a flat top portion including an elongated slot therethrough,

a mandrel assembly including a portion through said slot,

means within said housing connected to said mandrel assembly for moving the same longitudinally of said slot,

stationary post means in opposed relation on opposite sides of said slot, and said mandrel assembly including a substantially cylindrical bending mandrel pivotally supported on a vertical axis normal to the said flat top portion.

extending 15. The structure of claim 14 and in which the said mandrel assembly portion extending through the slot comprises a pivot about which said bending mandrel may pivot.

16. The structure of claim 14 and in which said bending mandrel includes a peripheral central rim forming a means adapted for kinking inwardly a wall of the tube being bent.

'17. A tube bending machine including:

a housing having a flat top portion having an elongated slot thereth rough,

a mandrel assembly including a lower member supported by roller wheels in engagement with guide members parallel to said slot,

means within said housing connected to said lower member for moving the same longitudinally of said slot,

connecting means on said lower member extending through said slot,

a bending mandrel overlying said flat top portion and supported by said connecting means extending through said slot, said connecting means and bending mandrel forming a part of said mandrel assembly, and

a pair of stationary post means in opposed relation on opposite sides of said slot, 

1. A machine comprising in combination: a housing, slidable means on said housing adapted to engage a piece of tube and bend it against stationary post means, means for sliding said slidable means, and tube cutting means mounted on said housing adapted to pivot on said housing into a position which does not interfere with the bending of said tube against said post means.
 2. The machine of claim 1 in which said tube cutting means comprises a hydraulic cylinder connected to a pointed shear blade operable to force said blade through a piece of tube carried by a notched support member, said cylinder and said notched support member carried by a cutter housing.
 3. The structure of claim 1 and including annular members above and below said bending mandrel to define a slot adapted to accommodate the tube to be bent.
 4. The machine of claim 1 in which said slidable means comprises an adjustable grooved mandrel, which groove is shaped to accept said tube and to approximate the desired bend.
 5. The machine of claim 4 in which said groove includes a kinker ridge to fold in the side of the tube during the bending operation.
 6. The apparatus of claim 5 including stop means on said housing adjacent said adjustable mandrel operable to force the bent tube out of said groove when the adjustable mandrel slides away from said post means.
 7. The apparatus of claim 6 in which said means for sliding comprises a hydraulic cylinder connected to said mandrel so as to slide said mandrel along guideway means in said housing.
 8. The apparatus of claim 7 in which said post means comprise rotatable posts on said housing on each side of said guideway means.
 9. The machine of claim 5 in which said tube cutting means comprises a hydraulic cylinder connected to a pointed shear blade operable to force said blade through a piece of tube carried by a notched support member, said cylinder and said notched support member carried by a cutter housing.
 10. The machine of claim 8 in which said tube cutting means comprises a hydraulic cylinder connected to a pointed shear blade operable to force said blade through a piece of tube carried by a notched support member, said cylinder and said notched support member carried by a cutter housing.
 11. A machine comprising in combination: a housing, slidable means extending out of said housing adapted to slide along a guide means, engage a piece of tube, and bend it against stationary post means positioned on each side of said guide means, means for sliding said slidable means operable to be activated manually, said slidable means includes a grooved mandrel, which groove is shaped to accept said tube and to approximate the desired bend, said groove includes a kinker ridge to fold in excess material in the walls of the tube during the bending operation.
 12. The apparatus of claim 11 including stop means on said housing adjacent said guide means positioned to force the bent tube out of said groove as the mandrel slides away from said post means.
 13. The apparatus of claim 12 in which said means for sliding comprises a hydraulic cylinder connected to said mandrel and said post means comprise rotatable posts on said housing on each side of said guide means.
 14. A tube bending machine including: a housing having a flat top portion including an elongated slot therethrough, a mandrel assembly including a portion extending through said slot, means within said housing connected to said mandrel assembly for moving the same longitudinally of said slot, stationary post means in opposed relation on opposite sides of said slot, and said mandrel assembly including a substantially cylindrical bending mandrel pivotally supported on a vertical axis normal to the said flat top portion.
 15. The structure of claim 14 and in which the said mandrel assembly portion extending through the slot comprises a pivot about which said bending mandrel may pivot.
 16. The structure of claim 14 and in which said bending mandrel includes a peripheral central rim forming a means adapted for kinking inwardly a wall of the tube being bent.
 17. A tube bending machine including: a housing having a flat top portion having an elongated slot therethrough, a mandrel assembly including a lower member supported by roller wheels in engagement with guide members parallel to said slot, means within said housing connected to said lower member for moving the same longitudinally of said slot, connecting means on said lower member extending through said slot, a bending mandrel overlying said flat top portion and supported by said connecting means extending through said slot, said connecting means and bending mandrel forming a part of said mandrel assembly, and a pair of stationary post means in opposed relation on opposite sides of said slot. 